Cast stone orreconstructed stone is a refinedartificial stone, a form ofprecast concrete. It is used as abuilding material to simulate natural-cutmasonry in architectural features such as facings and trim; for statuary; and forgarden ornaments. It may replace natural building stones includinglimestone,brownstone,sandstone,bluestone,granite,slate, andtravertine. Cast stone can be made from white or greycements, manufactured or natural sands,crushed stone or natural gravels, and can be coloured with mineral colouring pigments. It is cheaper and more uniform than natural stone, and allows transporting the bulk materials and casting near the place of use, which is cheaper than transporting and carving very large pieces of stone.
The earliest known use of cast stone was in theCité de Carcassonne, France, in about 1138.[1] It was first used extensively in London in the late 19th century[2] and gained widespread acceptance in America in the 1920s.[3][4]
One of the earliest developments in the industry wasCoade stone, a firedceramic form ofstoneware. Another well-known variety wasVictoria stone, which is composed of three parts finely crushed Mount Sorrel (Leicestershire) granite to one ofPortland cement, carefully mechanically mixed and poured into moulds. After setting the blocks are placed in a solution ofsilicate of soda toindurate and harden them. Many manufacturers turned out a very non-porous product able to resist corrosivesea air and industrial and residential air pollution.[5]
According toRupert Gunnis a Dutchman named Van Spangen set up an artificial stone manufactury at Bow in London in 1800 and later went into partnership with a Mr. Powell. The firm was broken up in 1828, and the moulds sold to a sculptor, Felix Austin.[6]
Today most artificial stone consists of finePortland cement-basedconcrete, placed to set in wooden, rubber-lined fiberglass or iron moulds. There are two common manufacturing methods, the dry tamp method and the wet cast process. In the dry tamp method, used for smaller pieces,zero-slump concrete is compacted in the mould by vibration; in the wet cast method, used for larger building elements including those with internal reinforcement or anchor fixings, wetter concrete is cast in the mould for 24 hours.[7] Moulds may be made of sand, wood, plaster, gelatin,[4] rubber-lined fiberglass, or iron; in the dry tamp method, they can be re-used.
In the US and some other countries, the industry standard for physical properties and raw materials constituents isASTM C 1364, the Standard Specification for Architectural Cast Stone.
In the UK and Europe, the usual standard isBS 1217: Cast stone - Specification. Under theEuropean Commission's "Construction Products Regulations" legislation,CE marking became mandatory in mid-2013 for certain construction products sold in Europe, including some cast stone items.[8]
One or more of the preceding sentences incorporates text from a publication now in thepublic domain: Bartlett, James (1911). "Stone". InChisholm, Hugh (ed.).Encyclopædia Britannica. Vol. 25 (11th ed.). Cambridge University Press. pp. 958–960.